This invention is directed to a trajectory compensating device which includes a rifle scope having a reticle which has both a primary and secondary sighting plane and the elevational turret of the rifle scope having a turret cap which carries an indicia carrying member having a calibration mark and an indicator mark which allows for maintaining the trajectory of the bullet within a certain variable limit with regards to the line of sight to the rifle scope across both the primary and secondary sighting planes of the reticle.
One of the common problems associated with the use of rifle scopes is the inability of the shooter to correctly gauge the distance between his firearm and the target such that the elevational controls of the rifle scope can be correctly adjusted to reflect the distance. In order to compensate for this lack of distance judging ability separate range finders and/or rifle scopes with built-in range finders have been developed. The problem with these systems, however, is that they require extra time to use and if the shooter is attempting to hit a moving target such as a running deer most of the time the shooter simply does not even have time to adjust the elevational and windage turrets let alone use these devices prior to having to take a shot at the target before it disappears.
In U.S. Pat. No. 3,386,330 this problem with range finders is discussed. This patent attempts to overcome this problem by providing not a true range finder but an estimate or rapidly usable range finder. Further, this patent discusses how a bullet size and the load used in the cartridge holding that bullet will effect the trajectory of the bullet. That is, the trajectory of the bullet can result in a reasonable estimation of a point of impact error.